As a sputtering method, a magnetron sputtering is dominant wherein a magnetic field generator provided with a plurality of magnets is placed behind a target to be treated. The magnetron sputtering is a method of forming high density plasma by forming a magnetic field on a target surface by a magnet and confining plasma near the target surface by utilizing a drift motion of electrons. A high-speed film depositing becomes possible as a result that high-density plasma presents near the target surface.
There are a variety of proposals of a magnetic field generator to be placed behind a target (for example, the patent document 1).